The invention relates generally to the reproduction of a master or original.
More particularly, the invention relates to the reproduction of a photographic master or original using a copier with a device for varying the magnification of the image. The copier further includes a support for holding the master in a predetermined plane, and a reflector which is movable into the optical path so as to deflect light out of the latter. The deflected light travels to a transparent viewing surface where an image of the master, or of a portion of the master, is formed for evaluation. The viewing surface and the predetermined plane are conjugates with reference to the reflector in the optical path.
In many copiers, the magnification is adjusted by a variable objective which is designed so that the distance between the support for the master and the carrier for the copy material need not be changed when the magnification is altered. With appropriate design of the variable objective, it is also possible to magnify the master beyond the point where the entire image fits on the copy material, i.e., it is possible to copy a segment of the master such that the image of the segment fills the available area of the copy material. Another procedure which can be used to make copies which conform optimally to the wishes of a customer is to move the support for the master relative to the optical path in the image plane. This enables off-center segments of the master to be copied.
A problem which arises is that of properly evaluating the relationship between the segment to be reproduced and the size of the copy material available at that time. Known devices for performing the evaluation and making adjustments have a reflector which is movable into the optical path and is inclined at 45 degrees to the latter. The reflector directs the light in the optical path onto a mat plate which is disposed in a conjugate image plane and is marked to show the different sizes of the positives. An image of the segment is formed on the mat plate and can be viewed from externally. However, the outside light causes difficulties for copiers operated in bright rooms.